Furnace seal means



Dec. 13, 1966 ALBERTSEN ET AL FURNACE SEAL MEANS Original Filed Jan. 7,1963 '7 Sheets-Sheet 1 INVENTORS. WILLARD ALBERTSEN, DAVID COPE 8 RALPHJ PERRINE Q m um g C? Q9 0% ATTORNEYS Dec. 13, 1966 w. ALBERTSEN ET AL3391,46

FURNACE SEAL MEANS Original Filed Jan. '7, 1963 7 Sheets-Sheet 2 fi i wvictim Q woml\ h w&

Dec. 13, 1966 w. ALBERTSEN ET AL 3,23%,468

FURNACE SEAL MEANS Original Filed Jan. 7, 1963 '7 Sheets-Sheet 5INVENTORS. WILLARD ALBERTSEN, DAVID COPE 8 R Dec. 13, 1966 w, 1 s ETAL3,291,468

FURNACE SEAL MEANS 7 Sheets-Sheet 4 Original Filed Jan. 7, 1963INVENTORS. WILLARD ALBERTSEN J ER RlNE wz. wwE

Dec. 13, 1966 w. ALBERTSEN ET AL 3,293,468

FURNACE SEAL MEANS 7 Sheets-Sheet 5 Original Filed Jan. '7, 1963INVENTORS. WILLARD ALBERTSEN, DAVID COPE D LH J. PERRINE Dec. 13, 1966w. ALBERTSEN ET AL 329L468 FURNACE SEAL MEANS Original Filed Jan. '7,1963 '7 Sheets-Sheet 6 FIG. 9

INVENTORS. WILLARD ALBERTSEN, DAVID COPE & RALPH J. PERRINE UnitedStates Patent 3,291,468 FURNACE SEAL MEANS Willard Albertsen and DavidCope, Salem, and Ralph J. lerriue, Colunibiana, Ohio, assignors to TheElectric Furnace Company, Salem, Ohio, a corporation of OhioContinuation of application Ser. No. 249,835, Jan. 7, 1963. Thisapplication May 5, 1965, Ser. No. 456,035 23 Claims. (Cl. 2663) Thisinvention relates in general to a furnace for continuous thermaltreatment of metallic strip materials, wherein the strip enters thefurnace and progresses at a substantially constant rate therethroughuntil thermal treatment has been completed, whereinafter the stripcontinues without interruption through the furnace exit means forrecoiling or the like.

This application is a continuation of and has copendency with our parentapplication, Serial No. 249,835, filed January 7, 1963, now abandoned.

In particular the invention relates to improved entrance and exit sealsrequired on furnaces adapted for continuous thermal treatment ofmetallic strip in which the treatment is conducted in a controlledprotective atmosphere such as substantially pure hydrogen or dissociatedammonia.

It is therefore among the objects of this invention to provideimprovements in furnace seal means which: prevent inward flow anddiffusion of air from the surrounding atmosphere into the furnace; allowappreciable internal pressure to be maintained in the furnace withoutexcessive loss of protective atmosphere gas; avoid dam age to themetallic strip by abrasion or other action to the surfaces thereof;accommodate irregularities in the metallic strip, such as splicesbetween successive coils, rough edges, and other irregularities withonly a minimum and brief increase in furnace atmosphere outflow; avoiddamage to the sealing means caused by strip irregularities; permitreplacement of worn or accidentally damaged parts without requiring thatthe furnace be taken out of operation for a period greater than actuallyrequired to make the immediate repairs; handle strip of various widthsand thicknesses without requiring special adjustments; tolerate stripwhich departs considerably from flatness in a transverse section;control movement of strip from entrance seal to exit seal to preventmisalignment of the strip within the furnace; and require very slighttension to advance the strip through the entrance and exit seals.

Seal means of many kinds are known in the prior art for use inconjunction with a so-called strip annealing furnace, and such meansinclude, among others, curtains of felt, asbestos cloth, and glasscloth. These means are sometimes employed as wipers and are held incontact with the work strip by mechanical pressure. Seals includingmetal rollers have also been attempted.

Experience has shown, however, that curtain or wiper type seals rapidlybecome ineffective because they are damaged by defects in the workstrip, such as ragged edges, slivers, splices and so forth.Additionally, detached slivers may become lodged in the curtains orwipers, and thereafter may scratch or otherwise damage the surface ofthe strip. In like manner, seals with metal rollers fail to provideadequate sealing, and also tend to scratch the surfaces of the workstrip.

It is a further object of our invention, therefore, to provide a rollerseal having non-metallic contact with the work strip, which is noteasily damaged, and is capable of easy repair as required.

The features of this invention, which are believed to be novel, are setforth with particularity in the appended claims. The invention itself,however, both as to its organization and use, together with furtherobjects and advantage thereof, may best be understood by reference tothe following description taken in conjunction with the accompanyingdrawings, in which:

FIGURE 1 is a sectional elevation of a preferred embodiment of theinvention taken on the line 11 of FIGURE 3;

FIGURE 2 is an elevational view of the preferred embodiment of theinvention shown in FIGURE 1 taken along the line 2-2 of FIGURE 3;

FIGURE 3 is a sectional fragmentary elevation of the preferredembodiment of the invention taken along the line 3--3 of FIGURE 1;

FIGURE 4 is a perspective exploded view of one of the roll seal meansemployed in the invention, and shown in association with end sealingmeans;

FIGURE 4A is a fragmentary perspective view of wiping means used inassociation with the roll seal means of FIGURE 4;

FIGURE 4B is a fragmentary perspective view of another embodiment ofwiping means used in association with the roll seal means of FIGURE 4;

FIGURE 5 is another embodiment of the invention shown in sectionalelevation and taken on the line 5-5 of FIGURE 7;

FIGURE 6 is an elevational view of the embodiment shown in FIGURE 5 andtaken on the line 6-6 of FIGURE 7;

FIGURE 7 is a fragmentary sectional elevation of the embodiment of theinvention shown in FIGURES 5 and 6 taken on the line 77 of FIGURE 5;

FIGURE 8 is a sectional elevational view of still another embodiment ofthe invention for use in conjunction with horizontal strip furnaces;

FIGURE 9 is a fragmentary sectional plan view of the embodiment of theinvention shown in FIGURE 8 taken on the line 8-8 of FIGURE 8;

FIGURE 10 is a fragmentary view of the ends of a pair of roll seal meansin sealing engagement with the work strip;

FIGURE 11 is an elevational sectional view of an alternative form ofleaf seal; and,

FIGURE 12 is a schematic control diagram of fluid pressure means toselectively operate each side of the roll seal.

Reference is now made to the drawings in greater detail, and inparticular to FIGURES 1, 2 and 3 wherein is shown in seal roll housing10, including vertical metal side plates 12 located outboard of themargins of the work strip W, and box forming angle members 14. The innerfaces 16 of plates 12 are finished true and smooth, and are positionedaccurately parallel. A passageway 18 formed by spacing angle members 14is of sutficient size to provide clearance for the maximum expectedstrip widths and any possible irregularities in the direction of strip,thickness, such as splices, damaged edges, and so forth.

A pair of rolls 20 and 22 having metal cores 24 are provided with stubshafts 26 and outer coverings 28. The outer coverings 28 are provided tomake contact with the work strip W at the pass line P of the furnacecomplex. These coverings are of rubber-like material, preferably havinggood wear resistance and toughness, and are capable of withstandingfairly high temperatures. Neoprene, silicone rubber, and other syntheticmaterials have proved satisfactory for this purpose. The neoprenecovering has been found to provide best results having a Shore DurometerA hardness in the range of 50 to 65.

The ends 30 of the roll bodies are finished to planes at right angles totheir axes of rotation, and the ends of the coverings 28 are also cut inalignment with these planes. Washers 32 of easily compressiblerubber-like material are provided at each end 30 of the rolls in contactwith the roll bodies 24 and with coverings 28.

(See also FIGURE 4.) In practice sponge neoprene of closed-cell type hasbeen used. For rolls of the order of 6 inches diameter and 30 inch bodylength, washers 32 of approximately 0.5 inch uncompressed thickness havebeen successfully employed. A central opening 34 is provided in eachwasher 32 of diameter to fit snugly around stub shaft 26.

Outwardly of each washer 32 is a rubbing washer 36, usually about 1 inchthickness and of diameter preferably slightly less than the rollcovering 28. Material for these rubbing washers should have lowcoefficient of friction and low rate of wear when operated in rubbingcontact with washers 32 or with a smooth metallic surface.Tetrafiuorethylene resins, such as manufactured under the trade nameTeflon, are well suited for this purpose. Metal seal washers 38,provided outwardly of rubbing washers 36, are of the same diameter asthe rubbing washers 36, and are usually inch to inch in thickness. Thesemetal seal washers 38 may be of carbon steel, stainless steel, ornonferrous metals such as bronze. Central openings in washers 36 and 38are of a diameter to provide running fits on stub shafts 26. In certainapplications, it is possible to omit rubbing washers 36 and use onlysponge washers 32 and metal washers 38. In such cases relative rotationusually occurs between washers 38 and housing side plates 12. Suitablelubricant may be applied through slots 40 to minimize the rate of wear.

Stub shafts 26 are mounted in self-aligning bearings 42, attached tobell cranks 44 and 46, which are pivotally mounted on shafts 48. Tomaintain parallelism between the axes of rolls 20 and 22, correspondingbell cranks on opposite sides of the rolls may be connected by stifftubular torsion members 50. A fluid motor 52 is attached to an extensionear 53 of each bell crank of at least one roll and may be used to urgethe rolls toward each other or away from each other. To constrain theroll axes to be equidistant from the pass line P at all times, bellcranks 44 and 46 may be provided with gear sectors 54 and 56 in meshingengagement at 58. For ease of maintenance and repair, slots 40 and 41are provided in each side plate 12 to facilitate quick removal of rolls20 and 22. Also, slots 40 and 41 serve to permit shifting of rolls 20and 22 toward and away from each other as is described with greatparticularity hereinafter.

In operation, the rolls 20 and 22 are urged toward each other withsufficient force to compress coverings 28 by a total amount slightlymore than the thickness of the work strip W, so that coverings 28 are incontact under some pressure beyond the edges of the work strip W, whichare thus enfolded thereby. As best shown in FIGURE 10, there is shownbut a small triangular space 64 not sealed by the work rolls 20 and 22.

A difliculty sometimes encountered in handling continuous strip is thatof imperfect tracking. Thus, a work strip W may be well centered betweenside plates 12 of the entrance seal assembly 10, but if the work striphas an edgewise curvature, or camber, one edge being slightly longerthan the other, the work strip may be considerably off center when itreaches the exit end of the furnace. With the present invention, usefulcontrol may be exercised over strip tracking by applying more rollpressure to the strip at one edge than at the other. With stiff torsionmembers 50, it is not feasible to change the pressure distribution to auseful extent. However, by making one or both torsion bars relativelyslender, as shown at 64 (FIGURE 1) rather than stiff tubular members 50,the bell cranks at one edge of the strip W may be displaced angularlyrelative to those of the other edge, with resulting differentialpressures exerted on the strip at the opposite edges thereof. Thisoperation causes the strip to change its position laterally to a usefulextent, and thus, compensates for tracking error caused by a camberedstrip.

In the embodiment of the invention shown in FIGURES 1, 2 and 3 aseparate fluid motor 52 is shown for each bell crank. However, with gearteethacting at 58, satisfactory operation can be had with a cylinderattached only to the pair of bell cranks on the same side of the strip.By varying the pressures in the cylinder or cylinders at one edge of thestrip relative to the cylinder or cylinders at the opposite edge, and byproviding yieldable spring torsion bars such as 64, the forces exertedby the rolls on the strip, and relative forces at the two edges, can beadjusted over a considerable range.

Various means for controlling air pressures may be resorted to, and anembodiment for illustrative purposes only is shown in FIGURE 12. Adetailed discussion of FIGURE 12 will be undertaken hereinbelowfollowing completion of the description of the seal means per se.

The seal assemblies described and discussed hereinabove provide forsealing between the work strip W and the rolls 20 and 22, and sealingbetween the roll ends 30 and the side plates 12. It still remains toprovide further sealing means tangential to the rolls 20 and 22, theside plates 12, and the housing angle members 14. With the rolls 20 and22 so encased, a complete seal is provided which accomplishes theobjects enumerated hereinabove.

To this end, flexible leaves 66 (see also FIGURE 4A), are placed intangential contact with the rolls 20 and 22, and are connected gastightto a transverse portion 68 of housing angles 14. Leaves 66 are providedwith sealing material such as wool felt 70 on their under surfaces andat edges adjacent to the side plates 12. This sealing material 70prevents or minimizes gas leakage therebetween, while permitting somemovement of the leaves normal to the roll peripheries. Leaves 66 aremade of sheet metal such as stainless steel, having a moderate springtemper. Each leaf is attached by fastening means 69 to flanges 72 oftransverse housing member angles 14. The edges of leaves 66 nearest tothe strip W are flanged upward, and the felt material 70 is attached tothe flanges by clamp strip 74 and fastening means 76. At flange 72 asimilar attachment is made.

In the entrance seal such as shown in FIGURE 1, the upper surfaces ofrolls 20 and 22 move away from the strip and toward the leaves 66,tending to drag felt facing 70 away from the free edges of leaves 66 andthereby placing the felt facing in tension, thus requiring that theedges 78 of the facing 70 be securely fastened at the clamp strip 74 ofthe leaf 66. In the alternative, the facing 70 may be fastenedpermanently to the leaves 66 by an adhesive.

FIGURE 4A illustrates the relationship between the edge of leaf 66 andside plates 12 when the felt or equivalent material is used as a facingsecured to the edges and underside of the leaf. An alternate arrangementis shown to the right thereof at FIGURE 4B wherein the facing 71 issecured by an adhesive to leaf 73 rather than clamping means employedwith leaf 66. In any event, leaves 66 and 73 are slightly shorter,parallel to the pass line, than the distance between the plates 12.Facings 70 and 71 are cut so as to extend beyond leaves 66 and 73respectively at 79 and 80 so as to rub against end plate surfaces 16while permitting the leaves to be bent upward. Atmospheric leakagebetween side plates 12 and leaves 66 or 73 is thus kept very minimal.

Yet another alternative leaf construction is shown in FIGURE 11, whereinthe leaf 82 is of solid metal and relatively thick. It rests by gravityat 84 on roll covering 28, and the leaf 82 is pivotally mounted on screw86 extending through each side plate 12 into a socket 88 in leaf 82.Rear edge 90 of leaf 82 and adjacent surface 92 of member 14 arefinished to cylindrical shape, concentric with screw 86. Packing groovesare formed in the side edge and rear edge surfaces of leaf 82 to receivepacking 94. Surrounding the depression 88 a packing recess is partlycircular, and packing strip 94 preferably is molded to fit in theserecesses. The packing protrudes far enough beyond the edge surfaces ofleaf 82 to make sealing contact with surfaces 92 and 16 of the sealhousing, while yet allowing pivotal motion about screws 86. The lowersurfaces of solid leaves 82 may, if desired, be faced with yieldablematerials such as wool felt, as is shown for leaves 66 in FIGURE 1, andpreferably bonded to the leaf 66 as shown in FIGURE 4B. Also, a facingof Teflon may be used.

General reference is now made to FIGURES 5, 6 and 7, wherein is shownyet another embodiment of the invention, and, in particular, alternatemeans for shifting the rolls 2t) and 22 into and out of a pressureengagement with the work strip W. In FIGURES 6 and 7, it will beobserved that a fluid motor 100 is drivingly connected to a slide 102 bymeans of a screw 104 and nut 106, the screw being secured to the airmotor, and the nut being secured to the slide, with gibs 108 beingprovided to guide the slide for limited vertical movement. Each roll isjournaled in a toggle plate 111) which is pivotally mounted at its lowerinboard corner 112 to a housing side plate extension ear 115, and ispivotally connected at its upper end to the slide 182 by a toggle link116. In order to maintain parallelism between the rolls 20 and 22, thetoggle plates 110 on opposite ends of the rolls are connected by torsiontubes 118. Thus in order to separate the rolls, fluid motor 100 isactuated to drive the slide 102 downwardly, whereby the toggle links 116urge the toggle plates 11!) arcuately apart from the pass line of theseal. Conversely, to pressure engage the rolls, the fluid motor isreversed whereupon the slide,102 is urged upwardly, thereby placing thetoggle links in tension, and arcuately pivoting toggle plates inwardlytoward the pass line of the seal. Because of the arcuate movement of therolls, arcuate slots 120 are provided in side plates 114 to receive stubshafts 122, and to accommodate arcuate movement thereof.

In view of the arcuate movement of the rolls 20 and 22, which issomewhat in excess of the arcuate movement of rolls shown in FIGURE 1,the sealing leaves 124 are inclined at about 30 to the horizontalengagement with the rolls during adjusting movement. Otherwise, the sealillustrated in FIGURES 5, 6 and 7 functions substantially in accordancewith the operation of the seal disclosed in FIGURES l, 2 and 3.

Reference is now made to FIGURES 8 and 9 which disclose an embodiment ofseals for use with horizontal strip travel. The seal housing of thisembodiment includes lower plate members 126, 128, 130 and upper plate132, and side plates 134. Lower roll 136, with fixed axis, and upperroll 138, having its axis shiftable vertically, are located with axes ina transverse vertical plane, for pressure engagement one with the other,for pressure engagement with a strip passing therebetween in ahorizontal plane. Each roll is provided with a set of end discsequivalent to the end discs illustrated in FIGURE 4. The elastomericcoverings 140 are also similar to the coverings for the rolls alreadydiscussed hereinabove. The stub shafts 26 of rolls 136 and 138 aremounted in takeup type self-aligning ball bearing units 142 fittedbetween guides 150, the two bearing units related to the lower roll 136being seated fixedly, and those related to the upper roll 138 beingmovable upwardly from the position shown.

A connecting link 146 is pinned to each of the two bearing units 142 ofupper roll 138. Each link 146 is also pinned to a lever 148, which isfulcrumed at 150 upon frame 152. Torsion bar 154 is attached between thetwo levers 148 and tends to hold roll 138 level, sub ject to suchtorsional deflection as may be permitted by the slenderness of bar 154.A fluid cylinder 156, at-

tached to frame 152 at 158, is pinned to each lever 148.

The force exerted by roll 138 upon roll 136 and work strip W dependsupon the size of cylinders 156 and the fluid pressure imposed on thecylinders. By virtue of the torsional deflection of torsion bar 154,roll 138 may be loaded more heavily at one side than the other ifdesired, as heretofore described relative to the embodiment of theinvention shown in FIGURES l, 2 and 3. The essential difference beingthat the embodiment in FIGURES 1, 2 and 3 is primarily suited forsealing the movement of vertical strip passing through the furnace,wherein both rolls may move away from the strip pass line. As alreadydiscussed, only the upper roll 138 moves in the embodiment shown inFIGURES 8 and 9. However, it will become readily apparent to thoseskilled in the art that with slight modification in the so-calledvertical design, it can be adapted for horizontal furnaces.

As in the vertical seal, a closure is also required in the horizontalseal between each roll and the roll housing. For this purpose sealleaves 160 and 162 are provided with compressible facings 164. Theleaves are clamped to housing flanges 166 and 168, and are spring urgedinto tangential contact with the rolls 136 and 138. For leaves of thistype and position, force other than direct gravity may berequired toinsure adequate sealing, and in this event spring or counter weightmeans may be added to the natural resilience of the leaf springsthemselves. For ease of maintenance, particularly with respect to thefrequency of replacing felt covers 164, the entrance seal will haveleaves 161) and 162 preferably located to the left or forward of theseal roll, whereas in the application for an exit seal it is preferableto mount the leaves on the right or extreme remote side of the sealrolls as shown in phantom.

Reference is now made to FIGURE 12, a schematic diagram illustrating ingeneral the application of the actuating cylinders of the seal rolls inany of the arrangements shown in the drawings, and in particular withreference to FIGURE 1. Four cylinders, 52A, 52B, 52C and 52D, are shownin pairs with each pair acting adjacent an edge of the work strip W. Asshown, pressure applied through lines 240A and 240B, will force therolls 20 and 22 toward the strip W, and pressure applied through lines241A and 241B, will separate the rolls.

More specifically, solenoid 4-way valve 243 is energized to allowpressure from the line 242A to enter line 242B and branch lines 243A and243B. The check valves 244A and 244B close and the pressure passesthrough adjustable pressure regulators which may take the form ofmanually operated pressure regulators 246A and 2468. Check valves 247Aand 247B open, the pressure by-passing throttle valves 248A and 2488.The pressure then enters cylinders 52 through lines 240A and 2408.Simultaneously air is exhausted through lines 241A and 24113, closingcheck valves 249A and 249B, and through throttle valves 251A and 25113to provide regulation of cylinder speed. The pressure then enters branchlines 252A and 252B, and thereafter is exhausted through line 253B andsolenoid 243 to line 253A.

To separate the rolls 20 and 22, solenoid 243 is energized to applypressure from line 242A through 4-way valve 243 and to line 253B. Thepressure by-passes throttle valves 251A and 251B, opens checks 249A and249B, and enters cylinders through lines 241A and 241B. Simultaneouslyair is exhausted from cylinders 52 through lines 240A and 24033, closingcheck valves 247A and 247B, and through throttle valves 248A and 2483.The exhausting fluid by-passes regulators 246A and 246B, opens checkvalves 244A and 2443 to branch lines 243A and 243B, and then entersmanifold 242B, exhausting through solenoid 243 and line 253A. Regulators246A and 246B may be adjusted to apply more pressure to one edge of thework strip W to guide strip that is tracking imperfectly.

To provide for substantially complete enclosure, apart from the actionof the seal rolls, between the internal protective atmosphere andexternal air at the entrance and exit seals, provision is made forseparate closure gates, located inwardly of the seal rolls. With suchgates, 21 good closure can be effected when it is desired to stop thestrip travel for various reasons, including repair of the roll seals.Reference, therefore, is made once more to FIGURES 1, 2 and 3 wherein isillustrated a closure gate including a lower housing member 170 attachedto member 14 of the roll seal housing, an upper member 172 attached tothe lower end flange 174 of the casing of a furnace F. Slots 176 and178, in members 170 and 172, respectively, are in alignment with slot 18of member 14 for passage of work strip W. Member 170 has a generallyfiat upper surface 180 terminating at ribs 182 which form channels forpacking material 184.

A pair of metal gates 186 and 187, rest on top of packing inserts 184which generally define a fiat support plane, but which are sufiicientlydeformable to provide sealing action at contact with gates 186 and 187.The inboard edges of gates 186 and 187 are slotted at 188 to receivepacking inserts 189 in opposed alignment one with the other. Gates 186and 187 are movable in a horizontal plane toward and from the pass lineof the work strip W, and are operably shiftable by a pair of screwshafts 190 and 192 having right and left hand threads respectively, andaligned at right angles to, and on opposite sides of, the pass line ofthe work strip W. These shafts are journaled in fittings 194 and 196 andhave packing means 198 to prevent gas leakage around the shaft. Thethreaded portions of the shafts engaged nuts 200 seated in receptacles202 of gates 186 and 187. Shafts 190 and 192 are caused to rotate inunison by sprockets 204, one on each shaft, which mesh with a continuouschain 206. mounted on at least one screw shaft. the shafts may be motordriven.

When gates 186 and 187 are closed, they are effectively sealed at theirabutting edges against work strip W by means of packing inserts 189, andalso beyond the edges of the work strip W by contact of said packinginserts 189. Packing inserts 184 seal against gates 186 and 187 at theplane of their lower surfaces. Thus there is very little leakage pastgates 186 and 187 when closed, if the packings are in proper condition.With the gates closed, furnace operation may be suspended with smallloss of protective atmosphere. Repairs and adjustments may be made whenneeded, to the various elements of the seal roll means outboard of thegates 186 and 187. In preparation for repair work upon the seal rolls,seal leaves, and associated parts, inert gas such as nitrogen may beadmitted to the space below the closure gates 186 and 187 throughsuitable means such as inlet 210 (see FIGURE 3) from any source notshown.

In the embodiment of the invention shown in FIGURES 8 and 9, a modifiedform of closure gate has been found to be satisfactory. In thisembodiment, a closure gate 211 is provided to the right of the sealrolls 136 and 138, and is suspended by a link 212 from a lever 214 neareach side plate 134. Levers 214 are attached to rotable shaft 216 whichextends through one side plate 134 and has suitable packing to preventgas leakage. Another lever 218 is attached to the piston rod ofactuating cylinder 220 and to lever 214. Gate 211 has packing strip 222in its lower edge suitably fitted in channel means provided for thispurpose, and with a full downward stroke, this packing strip engages apacking strip 224 positioned in channels in a stationary still member226, the contact occurring at a level slightly below the work strip passline. With moderate tension, the work strip may be deflected as much asnecessary without difficulty. The gate 211 has a smooth vertical surfaceto bear against a transverse packing strip 228 suitably positioned in aslotted packing retaining jamb plate 230. The gate 211 also bearsagainst a vertical packing strip 232 also inserted in a slotted verticalportion of jamb plate 230. Pressure means, including pressure roller234, bell crank 236 and spring 238 are located on each side to insuresealing contact between gate 211 and packing strips 224 and 228.

In the alternative,

A hand wheel 208 may be.

In operation of the invention, it is desired to apply only such force tothe rolls toward the pass line of the work strip W that the elastomericroll coatings are flattered enough to insure sealing on normally smoothstrip, and to flatten such strip should it become somewhat curvedtransversely. In the event that an imperfection such as a splice or adamaged area reaches the seal rolls, the roll coverings are sufficientlyyieldable to enable separation sufficiently to pass the imperfection andthen promptly reclose with very little increase of total force exertedby the rolls. To improve tracking, greater roll pressure may be appliednearer to one edge of the work strip W than to the other edge.

Thus in reading the foregoing discussion and description of theinvention taken in conjunction with the drawings, it will be understoodthat the subject invention is an improved means for sealing furnacesadapted for continuous thermal treatment of strip being introduced intoone end of a furnace and leaving the opposite end without interruptionof movement.

It is to be further understood, that whereas several embodiments of theinvention have been described hereinabove, these embodiments are by wayof example only and are not intended to be construed in a limitingsense. Other arrangements and modifications will occur to those skilledin the art upon reading this specification and the attached claims, andupon examination of the included drawings, said other arrangements andmodifications being within the spirit and scope of the invention asclaimed.

We claim:

1. In a furnace for continuous thermal treatment of metallic striphaving an opening therein for passage of strip, the improvement in sealmeans to seal said strip and furnace at said opening and comprising:housing means secured to said furnace and surrounding said opening; apair of rolls, each having shafts extending from opposite ends andmounted in side plates of said housing means transverse to and onopposite sides of the pass line of said strip; each side plate havingmeans for receiving one of the oppositely extending shafts of the sameone of said rolls to permit shifting of said one roll toward and awayfrom said other roll; means to shift said one roll into and out ofsealing contact with said strip; means to seal the ends of said rollswith the inwardly facing surfaces of said side plates, and means to sealthe peripheries of said rolls with said housing.

2. The device set forth in claim 1, including gate means between saidfurnace and said seal means to seal said opening when said one roll isshifted away from said other roll.

3. The device set forth in claim 1, wherein the peripheries of saidrolls have bonded thereto a uniform layer of resilient elasticsubstantially heat resistant material.

4. The device set forth in claim 1, wherein the said means to seal theperipheries of said rolls with said housing comprise: a pair of trunnionmounted leaves pivotally secured to straight side walls of said housing;curved rear wall portions of said housing adapted to maintain contactwith the back edges of said leaves during limited pivotal movementthereof about said trunnions; packing means secured to the side and backedges of said leaves for rubbing contact with the straight side andcurved rear wall portions of said housing; and facing material securedto the roll contacting faces of said leaves for rubbing contact withrespective peripheries of said rolls.

5. The device set forth in claim 1, wherein the means to seal betweenthe peripheries of said rolls and said housing comprises: a pair ofresilient leaves, each secured in relative gastight sealed contact tothe inner walls of said housing, and in biased tangential gastightcontact with an adjacent roll.

6. The device set forth in claim 5, wherein said leaves are of springtemper steel, lined on their roll contact surfaces With soft fibrousmaterial.

7. The device as set forth in claim 1, wherein said other roll isjournaled in said housing for rotation about a fixed axis; said rollshifting means including a pair of levers each pivotally fastened at oneend to said furnace, connecting links each pivotally fastened at one endto the free end of one of said levers and at the opposite end to one ofsaid shafts of said one roll; and motor means secured to said furnaceand to each of said levers adapted to shift said one roll relative tosaid other roll.

8. The device set forth in claim 7, wherein said motor means includes apair of motors each secured to one of said levers, and motor controlmeans to selectively actuate each said motor to provide for differentroll pressures at opposite ends of said rolls.

9. The device set for in claim 1, wherein each of said side plates hasadditional means for receiving one of the oppositely extending shafts ofsaid other roll to permit shifting of said other roll toward and awayfrom said first roll; and a pair of roll journal means each shiftablymounted on one of said side plates and to receive said shafts thereinand to permit said roll shafts to be shifted in said receiving means.

10. The device set forth in claim 9, including a pair of torque rodssecured in parallel between the roll journal means and on opposite sidesof the strip plane.

11. The device set forth in claim 9, including a pair of torque rodssecured in parallel between the roll journal means on opposite sides ofthe rolls, one of said rods being yieldable to the application of torquethereto.

12. The device set forth in claim 9, including a pair of torque rodssecured in parallel between the roll journal members on opposite sidesof said rolls, one of said torque rods being substantially unyieldableto the application of torque applied thereto.

13. The device set forth in claim 9, including a pair of tubular torquerods secured in parallel between the roll journal members on oppositesides of said rolls, one of said torque rods being substantiallyunyieldable to the application of torque applied thereto.

14. The device set forth in claim 9, including a pair of torque rodssecured in parallel between the roll journal members on opposite sidesof said rolls, one of said torque rods being tubular and relativelyunyieldable to the application of torque applied thereto, and the othertorque rod being solid and yieldable to the application of torquethereto.

15. The device set forth in claim 9, wherein each said roll journalmeans includes a shiftable plate pivotally secured at its lower portionto a side plate; plate shifting means; and connecting means pivotallysecured to the upper portion of said shiftable plate and to said plateshifting means, whereby shiftable movement is imparted to a roll uponactuation of said shifting means.

16. The device set forth in claim 9, including motor means; slide meansshiftable by said motor means; roll journal means each comprising atoggle plate pivotally secured at its lower portion to a side plate;toggle links pivotally connecting said toggle plates to said slide,whereby selective shifting of said slide by said motor means moves saidpair of rolls toward and away from each other.

17. The device set forth in claim 9, wherein said roll journal meanseach comprise a bell crank pivotally secured to a side plate; one arm ofsaid bell crank being secured to a roll shaft; and bell crank shiftingmeans secured to the other arm of said bell crank to shift said bellcrank about its pivotal axis.

aaenaes 18. The device set forth in claim 9, wherein said roll journalmeans comprise a pair of bell cranks pivotally secured to each sideplate; one arm of each bell crank being secured to a roll shaft; bellcrank shifting means secured to at least one of said bell cranks; andsector gears formed on the heels of said bell cranks for meshingengagement, whereby shifting of one bell crank about its pivotal axiswill cause the other bell crank to shift in an equal and oppositedirection about its pivotal axis.

19. The device set forth in claim 9, wherein said roll journal meanscomprise a pair of bell crank members pivotally secured to each sideplate; one arm of each bell crank being secured to a roll shaft; bellcrank shifting means secured to each of said bell cranks; a relativelyrigid torque rod interconnecting corresponding bell cranks on oppositesides of a roll; a torque rod yieldable to torque applied theretointerconnecting corresponding bell cranks on opposite sides of the otherof said rolls; and means to actuate said shifting means to selectivelyprovide for different roll pressures at opposite ends thereof.

20. The device set forth in claim 9, wherein said roll end seal meanscomprises a compressible washer having a center opening adapted to fitsnugly about the roll shaft, said washer being of substantially the sameouter diameter as its adjacent roll; a rigid washer positioned betweensaid compressible washer and one of said side plates and having a centeropening provided with a running fit on said roll shaft, each said shaftreceiving means being covered by one of said washers and being of alength to provide total movement of said roll shaft therein withoutbreaking the seal between said plate and said washer.

21. The device set forth in claim 9, wherein said roll end seal meanscomprises a compressible washer having a center hole adapted to fitsnugly about the roll shaft, said washer being of substantially the sameouter diameter as the outer diameter of said roll and being adjacentthereto; a plastic washer adjacent said compressible Washer having acenter hole provided with a running fit on said roll shaft and being inouter diameter slightly less than the outer diameter of saidcompressible washer; and a rigid wear resistant washer having a runningfit with said roll stub shaft and being substantially the same diameteras said plastic washer, and being positioned between said plastic washerand one of said side plates.

22. The device set forth in claim 21, wherein the distance between saidside plates is selected to compress each compressible washer tosubstantially one-half of its free thickness when at least one of saidother washers is in place between said compressible washer and one ofsaid side plates.

23. The device as set forth in claim 9, including means for yieldinglymaintaining said rolls generally parallel while permitting sufiicientvariations therefrom to accommodate desired variations in roll pressuredistribution.

References Cited by the Examiner UNITED STATES PATENTS 890,252 6/1908Thompson 263-3 1,633,121 6/1927 Minton 34-242 2,367,174 1/1945 Renkin2663 2,654,587 10/1953 Skivesen 266-3 2,890,878 6/ 1959 Steinherz 34242JOHN F. CAMPBELL, Primary Examiner. J. M. ROMANCHIK, JR., Examiner.

1. IN A FURNACE FOR CONTINUOUS THERMAL TREATMENT OF METALLIC STRIPHAVING AN OPENING THEREIN FOR PASSAGE OF STRIP, THE IMPROVEMENT IN SEALMEANS TO SEAL SAID STRIP AND FURNACE AT SAID OPENING AND COMPRISING:HOUSING MEANS SECURED TO SAID FURNACE AND SURROUNDING SAID OPENING; APAIR OF ROLLS, EACH HAVING SHAFTS EXTENDING FROM OPPOSITE ENDS ANDMOUNTED IN SIDE PLATES OF SAID HOUSING MEANS TRANSVERSE TO AND ONOPPOSITE SIDES OF THE PASS LINE OF SAID STRIP; EACH SIDE PLATE HAVINGMEANS FOR RECEIVING ONE OF THE OPPOSITELY EXTENDING SHAFTS OF THE SAMEONE OF SAID ROLLS TO PERMIT SHIFTING OF SAID ONE ROLL TOWARD AND AWAYFROM SAID OTHER ROLL; MEANS TO SHIFT SAID ONE ROLL INTO AND OUT OFSEALING CONTACT WITH SAID STRIP; MEANS TO SEAL THE ENDS OF SAID ROLLSWITH THE INWARDLY FACING SURFACES OF SAID SIDE PLATES, AND MEANS TO SEALTHE PERIPHERIES OF SAID ROLLS WITH SAID HOUSING.